- #1
dincerekin
- 10
- 0
Homework Statement
A thin plastic spherical shell of radius a is rubbed all over with wool and gains a charge of -Q. What is the potential relative to infinity at location B, a distance a/3 from the centre of the sphere?
Homework Equations
[tex] \text{$\Delta $V}=\int _{\text{initial}}^{\text{final}}{E}.d{l} [/tex]
The Attempt at a Solution
since the potential difference between any 2 points in a spherical shell is 0, point B can be anywhere in the sphere (it doesn't have to be a/3 from the centre).
so if we take point B as a point, an infinitesimal distance away from the shell (still inside the shell)
then we can treat the shell as a point charge:
[tex] \text{$\Delta $V}=\int _{\infty }^a\frac{1}{4\pi \epsilon }\frac{Q}{r^{2}}dr [/tex]
which just gives:
[tex] \frac{1}{4\pi \epsilon }\frac{Q}{a} [/tex]i don't think this answer is right. So, wheres the flaw in my logic, and how are you meant to do this question?
(edit: the epsilons are meant to have a 0 subscript)
Last edited: